High Mortality Decline With One-Dose Varicella Vaccine

MONDAY, July 25 (HealthDay News) -- Overall varicella mortality decreased by 88 percent following implementation of the one-dose vaccination program, with a 96 percent decrease in individuals aged younger than 50 years, according to a study published online July 25 in Pediatrics.

Mona Marin, M.D., from the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues investigated the impact of vaccination on varicella mortality in the first 12 years of the U.S. varicella vaccination program. They updated the U.S. varicella mortality data analysis, and calculated the age-adjusted and age-specific mortality rates for the period from 2002 to 2007, and examined the trends since the pre-vaccine years. National data from the U.S. National Center for Health Statistics' Mortality Multiple Cause-of-Death records were collected for deaths for which varicella was either the underlying or contributing cause.

The investigators found that the average mortality rate for varicella during the one-dose vaccination program showed an overall decline of 88 percent, from 0.41 per million population in 1990-1994 to 0.05 per million population in 2005-2007. Mortality rates declined among all age groups with extremely high decrease among children and adolescents younger than 20 years (97 percent), and participants younger than 50 years (96 percent). Compared with an annual average of 13 and 16 deaths during pre-vaccine years for children aged 1 to 4 and 5 to 9 years, respectively, the number of deaths between 2002 and 2007 declined to 3 deaths per age range.

"The impressive decline in varicella deaths can be directly attributed to successful implementation of the one-dose vaccination program," the authors write.